Nav: Home

'Super yeast' has the power to improve economics of biofuels

October 17, 2016

MADISON, Wis. -- Scientists at the University of Wisconsin-Madison and the Great Lakes Bioenergy Research Center (GLBRC) have found a way to nearly double the efficiency with which a commonly used industrial yeast strain converts plant sugars to biofuel. The newly engineered "super yeast" could boost the economics of making ethanol, specialty biofuels and bioproducts.

Though Saccharomyces cerevisiae has been the baker's and brewer's yeast of choice for centuries, it poses a unique challenge to researchers using it to make biofuel from cellulosic biomass such as grasses, woods, or the nonfood portion of plants. The world-famous microbe is highly adept at converting a plant's glucose to biofuel but is otherwise a picky eater, ignoring the plant's xylose, a five-carbon sugar that can make up nearly half of all available plant sugars.

"For cellulosic biofuels to become economically feasible, microbes need to be able to convert all of a plant's sugars, including xylose, into fuel," says Trey Sato, the GLBRC study's lead researcher and a UW-Madison associate scientist.

In a study published Friday (Oct. 14, 2016) in the journal PLOS Genetics, Sato and his GLBRC collaborators describe the isolation of specific genetic mutations that allow S. cerevisiae to convert xylose into ethanol, a finding that could transform xylose from a waste product into a source of fuel. To uncover these genetic mutations, the researchers had to untangle millions of years of evolution, teasing out what led S. cerevisiae to become so selective in its eating habits in the first place.

First, Sato and colleagues gave the yeast a choice akin to eating carrots for dinner or nothing at all, surrounding S. cerevisiae with xylose until it either reevaluated its distaste for xylose or died. It took 10 months and hundreds of generations of "directed evolution" for Sato and his colleagues, including co-corresponding authors Robert Landick, a UW-Madison professor of biochemistry, and Audrey Gasch, a UW- Madison professor of genetics, to create a strain of S. cerevisiae that could ferment xylose.

Once the researchers had isolated the super yeast they named GLBRCY128, they also needed to understand exactly how the evolution had occurred in order to replicate it. Gasch compared Y128's genome to the original strain, combing through the approximately 5,200 genes of each to find four gene mutations responsible for the adapted behavior. To verify their finding, the researchers manually deleted these mutations from the parent strain, producing the same result.

Sato says this work could enable a wide variety of biofuels research going forward. With the technique for making Y128 published, researchers are free to make it themselves for the purposes of applying it to new biomass pretreatment technologies or to different plant materials. "Scientists won't need to adapt their research to the process that we're doing here," he says. "They can just take our technology and make their own strain."

Future research may also focus on the super yeast's potentially powerful role in creating specialty biofuels and bioproducts.

"We want to take this strain and make higher-order molecules that can be further converted into jet fuels or something like isobutanol, lipids or diesel fuel," says Sato. "And if we know how to better metabolize carbon, including xylose, anybody in theory should be able to rewire or change metabolic pathways to produce a variety of biofuel products."
-end-
--Mark E. Griffin, (608) 890-2168, mark.griffin@wisc.edu

DOWNLOAD PHOTOS: https://uwmadison.box.com/v/super-yeast

University of Wisconsin-Madison

Related Evolution Articles:

An evolution in the understanding of evolution
In an open-source research paper, a UVA Engineering professor and her former Ph.D. student share a new, more accurate method for modeling evolutionary change.
Chemical evolution -- One-pot wonder
Before life, there was RNA: Scientists at Ludwig-Maximilians-Universitaet (LMU) in Munich show how the four different letters of this genetic alphabet could be created from simple precursor molecules on early Earth -- under the same environmental conditions.
Catching evolution in the act
Researchers have produced some of the first evidence that shows that artificial selection and natural selection act on the same genes, a hypothesis predicted by Charles Darwin in 1859.
Guppies teach us why evolution happens
New study on guppies shows that animals evolve in response the the environment they create in the absence of predators, rather than in response to the risk of being eaten.
Undercover evolution
Our individuality is encrypted in our DNA, but it is deeper than expected.
Evolution designed by parasites
In 'Invisible Designers: Brain Evolution Through the Lens of Parasite Manipulation,' published in the September 2019 issue of The Quarterly Review of Biology, Marco Del Giudice explores an overlooked aspect of the relationship between parasites and their hosts by systematically discussing the ways in which parasitic behavior manipulation may encourage the evolution of mechanisms in the host's nervous and endocrine systems.
Tracing the evolution of vision
The function of the visual photopigment rhodopsin and its action in the retina to facilitate vision is well understood.
Directed evolution comes to plants
Accelerating plant evolution with CRISPR paves the way for breeders to engineer new crop varieties.
Pain free, thanks to evolution
African mole-rats are insensitive to many different kinds of pain.
Evolution in the gut
Evolution and dietary habits interact and determine the composition of bacteria in the digestive tract.
More Evolution News and Evolution Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Rethinking Anger
Anger is universal and complex: it can be quiet, festering, justified, vengeful, and destructive. This hour, TED speakers explore the many sides of anger, why we need it, and who's allowed to feel it. Guests include psychologists Ryan Martin and Russell Kolts, writer Soraya Chemaly, former talk radio host Lisa Fritsch, and business professor Dan Moshavi.
Now Playing: Science for the People

#538 Nobels and Astrophysics
This week we start with this year's physics Nobel Prize awarded to Jim Peebles, Michel Mayor, and Didier Queloz and finish with a discussion of the Nobel Prizes as a way to award and highlight important science. Are they still relevant? When science breakthroughs are built on the backs of hundreds -- and sometimes thousands -- of people's hard work, how do you pick just three to highlight? Join host Rachelle Saunders and astrophysicist, author, and science communicator Ethan Siegel for their chat about astrophysics and Nobel Prizes.